Move compile::Ctx to its own mod, compile::ctx::Ctx

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/main.rs

@@ -43,7 +43,7 @@ fn main() -> Result<()> {
     let ast = parser.next_body()?;
     //println!("{:#?}", ast);
     
-    let mut ctx = compile::Ctx::new();
+    let mut ctx = compile::ctx::Ctx::new();
     ctx.name_stack_mut().push_default();
     {
         let mut collect_names = compile::name::CollectNames::new(&mut ctx, text.as_str());